• Bulletin of the Korean Chemical Society
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• 제10권2호
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• pp.167-171
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• 1989

Kinetic energy release in the fragmentation of tert-butylbenzene molecular ion was investigated using mass-analyzed ion kinetic energy spectrometry. Method to estimate kinetic energy release distribution (KERD) from experimental peak shape has been explained. Experimental KERD was in good agreement with the calculated result using phase space theory. Effect of dynamical constraint was found to be important.

• 한국환경복원기술학회지
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• 제5권6호
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• pp.49-63
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• 2002

While the existing feng-shui is largely approached architecturally and geographically as positive place and negative place, the study is characterized by approaching and analyzing poong-soo environmentally. The theory of Eco-city as one of modern-city theories is worthy of studying by analyzing the merits and demerits of it and combining it with poong-soo and making a new alternative theory. Theory of Natural Energy and principle of Natural Balance. Thus, poong-soo ideas can be an important view of nature in analyzing the theory of Eco-city which is coming to the front these days. In particular, we try to make use of poong-soo as a basic theory for a city planning and design by studying and analyzing and combining the merits and demerits of Eco-city with poong-soo and presenting a new alternative method of a stable and balanced "refined city development". On the other hand, we connect 'theory with practice(or experience)' by covering all spaces variably from minimum unit space to city-space from the standpoint of poong-soo. But, problem of the Theory of Eco-city from the view of poong-soo are too artificial and theoretical, even if ideal. Conversely, from the view of Eco-city, the possibility of the practicability of Korean poong-soo is judged to be high. we can tell that among capital cities applied by poong-soo, historical cities like Beijing in China, Seoul in Korea and Tokyo in Japan are poong-soo cities in accordance with the requirements of Eco-city.

• Bulletin of the Korean Chemical Society
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• 제33권4호
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• pp.1213-1219
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• 2012

The reorganization energy and the spectroscopic properties of 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'- yl)naphthalene (DH-TNT) and 2,6-bis(5'-hexyl-thieno[3,2-b]thiophene-2'-yl)anthracene (DH-TAT), which are composed of an acene unit and alkylated thienothiophene on both sides, as organic materials for display devices were calculated and the results were compared with experimental values. The lower reorganization energy of the DH-TAT over the DH-TNT calculated by the density functional theory is attributed to a smaller vibrational distortion because of the heavier building block of DH-TAT, and it shows a good field effect performance over the DH-TNT. The calculated spectra and the other spectroscopic characteristic of the compounds are well consistent with those of observed results.

• Advances in aircraft and spacecraft science
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• 제4권3호
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• pp.269-280
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• 2017

The natural vibration analysis of microbeams resting on visco-Pasternak's foundation is presented. The thermoelasticity theory of Green and Naghdi without energy dissipation as well as the classical Euler-Bernoulli's beam theory is used for description of natural frequencies of the microbeam. The generalized thermoelasticity model is used to obtain the free vibration frequencies due to the coupling equations of a simply-supported microbeam resting on the three-parameter viscoelastic foundation. The fundamental frequencies are evaluated in terms of length-to-thickness ratio, width-to-thickness ratio and three foundation parameters. Sample natural frequencies are tabulated and plotted for sensing the effect of all used parameters and to investigate the visco-Pasternak's parameters for future comparisons.

• Journal of Electrical Engineering and information Science
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• 제3권2호
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• pp.267-273
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• 1998

This paper introduces an adaptive algorithm determining the measurement-track association problem in multi-target tracking(MTT). We model the target and measurement relationships with mean field theory and then define a MAP estimate for the optimal association. Based on this model, we introduce an energy function defined over the measurement space, that incorporates the natural constraints for target tracking. To find the minimizer of the energy function, we derived a new adaptive algorithm by introducing the Lagrange multipliers and local dual theory. Through the experiments, we show that this algorithm is stable and works well in general environments. Also the advantages of the new algorithm over other algorithms are discussed.

• Bulletin of the Korean Chemical Society
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• 제24권6호
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• pp.763-770
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• 2003

The $BH_5$ molecule, which is suggested as an intermediate of the acidolysis of $BH_4^-$, contains a weak two-electron-three-center bond and it requires extremely high-level of theories to calculate the energy and structure correctly. The structures and energies of $BH_5$ and the transition state for the hydrogen scrambling have been studied using recently developed multi-coefficient correlated quantum mechanical methods (MCCMs). The dissociation energies and the barrier heights agree very well with the previous results at the CCSD(T)/ TZ(3d1f1g, 2p1d) level. We have also calculated the potential energy curves for the dissociation of $BH_5$ to $BH_3$ and $H_2$. The lower levels of theory were unable to plot correct potential curves, whereas the MCCM methods give very good potential energy curves and requires much less computing resources than the CCSD(T)/ TZ(3d1f1g,2p1d) level. The potential energy of the $BH_5$ scrambling has been obtained by the multiconfiguration molecular mechanics algorithm (MCMM), and the rates are calculated using the variational transition state theory including multidimensional tunneling approximation. The rate constant at 300 K is 2.1 × $10^9s^{-1}$, and tunneling is very important.

• 한국가스학회지
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• 제23권1호
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• pp.1-11
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• 2019

한국 정부는 액화 천연가스를 대체하는 에너지원으로서 러시아의 파이프라인 천연가스 도입을 1990년대 이후부터 지속적으로 모색해오고 있다. 이러한 동북아 에너지 협력에 대한 논의가 현실 정치뿐만 아니라 학술적인 차원에서도 다양하게 진행되고 있지만, 기존의 선행연구들은 협력의 당위성만을 제시하고 있을 뿐이지 이론적 분석틀이 미약하다는 한계를 지니고 있다. 이에 본 논문에서는 경제통합론이라는 이론적 자원을 바탕으로 에너지협력의 동기 조건 단계를 분석하고자 한다. 연구 결과 동북아 천연가스 협력과 관련해서는 경제적 동기만이 유일하기는 하지만, 실질적인 기대이익뿐만 아니라 경제구조의 보완성과 정책목표의 수렴성이라는 조건들이 갖추어진 것으로 파악되었다. 결론적으로 동북아에서 높은 수준의 에너지 협력은 어렵겠지만 특혜무역협정 수준의 초보적인 천연가스 협력이 가능하다는 전망이 제시될 수 있었다.

• Computers and Concrete
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• 제26권1호
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• pp.31-52
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• 2020

This paper investigates the size dependent effect on the vibration analysis of a porous nanocomposite viscoelastic plate reinforced by functionally graded-single walled carbon nanotubes (FG-SWCNTs) by considering nonlocal strain gradient theory. Therefore, using energy method and Hamilton's principle, the equations of motion are derived. In this article, the effects of nonlocal parameter, aspect ratio, strain gradient parameter, volume fraction of carbon nanotubes (CNTs), damping coefficient, porosity coefficient, and temperature change on the natural frequency are perused. The innovation of this paper is to compare the effectiveness of each mentioned parameters individually on the free vibrations of this plate and to represent the appropriate value for each parameter to achieve an ideal nanocomposite plate that minimizes vibration. The results are verified with those referenced in the paper. The results illustrate that the effect of damping coefficient on the increase of natural frequency is significantly higher than the other parameters effect, and the effects of the strain gradient parameter and nonlocal parameter on the natural frequency increase are less than damping coefficient effect, respectively. Furthermore, the results indicate that the natural frequency decreases with a rise in the nonlocal parameter, aspect ratio and temperature change. Also, the natural frequency increases with a rise in the strain gradient parameter and CNTs volume fraction. This study can be used for optimizing the industrial and medical designs, such as automotive industry, aerospace engineering and water purification system, by considering ideal properties for the nanocomposite plate.

• 전기의세계
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• 제30권4호
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• pp.219-226
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• 1981

The magnetic field distribution in saturable iron part of electromagnetic energy conversion divices is defined by the nonlinear quasi-Poisson enquation that is described the electromagnetic field characteristics and satisfied the natural boundary condition. The solution of this equation is obtained by minimizing an energy functional by means of trial function that defined in triangular subregion of two-dimensional field region. As a result, the accuracy of the machine design is increased by use of its solution. In this respect, this study is developed the basic theory to analyze the magnetic flux distribution in saturable iron part and air gap of induction motor that its secondary part is short circuit by the variational principle, the minimized theory of energy functional, the application of F.E.M., and treatment of computer. As theoritical data compared with the practics, the validity of the theory in this study is supported by experimental findings.

• Steel and Composite Structures
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• 제26권6호
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• pp.663-672
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• 2018

This paper contains a consistent couple-stress theory to capture size effects in Euler-Bernoulli nano-beams made of three-directional functionally graded materials (TDFGMs). These models can degenerate into the classical models if the material length scale parameter is taken to be zero. In this theory, the couple-stress tensor is skew-symmetric and energy conjugate to the skew-symmetric part of the rotation gradients as the curvature tensor. The material properties except Poisson's ratio are assumed to be graded in all three axial, thickness and width directions, which it can vary according to an arbitrary function. The governing equations are obtained using the concept of minimum potential energy. Generalized differential quadrature method (GDQM) is used to solve the governing equations for various boundary conditions to obtain the natural frequencies of TDFG nano-beam. At the end, some numerical results are performed to investigate some effective parameter on buckling load. In this theory the couple-stress tensor is skew-symmetric and energy conjugate to the skew-symmetric part of the rotation gradients as the curvature tensor.